app/views/devise/registrations/new.html.erb
<div class="container">
<div id="loginbox" class="mainbox col-md-6 col-md-offset-3 col-sm-8 col-sm-offset-2">
<div class="panel panel-primary">
<div class="panel-heading">
<div class="panel-title">Sign-Up</div>
</div>
<div style="padding-top:30px" class="panel-body">
<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name), html: { role: "form" }) do |f| %>
<%= devise_error_messages! %>
<div style="margin-bottom: 25px" class="input-group">
<span class="input-group-addon"><i class="fa fa-envelope"></i></span>
<%= f.email_field :email, required: true, autofocus: true, class: "form-control", :placeholder => "Email" %>
</div>
<div style="margin-bottom: 25px" class="input-group">
<span class="input-group-addon"><i class="fa fa-asterisk"></i></span>
<%= f.password_field :password, required: true, class: "form-control", :placeholder => "Password", hint: ("#{@minimum_password_length} characters minimum" if @minimum_password_length) %>
</div>
<div style="margin-bottom: 25px" class="input-group">
<span class="input-group-addon"><i class="fa fa-asterisk"></i></span>
<%= f.password_field :password_confirmation, required: true, class: "form-control", :placeholder => "Confirm Password" %>
</div>
<div style="margin-top:10px" class="form-group">
<%= f.submit "Sign-Up", class: "btn btn-primary" %>
</div>
<div id="loginborder">
<%= render "devise/shared/links" %>
</div>
<% end %>
</div>
</div>
</div>
</div>